macro_rules! op {
    ($a: expr, $b: expr, $c: expr) => {
        match $c {
            1 => $a + $b,
            2 => $a - $b,
            3 => $a * $b,
            4 => $a / $b,
            5 => $a % $b,
            _ => -1,

        }
    }
}

fn main() {
    println!("{}", op!(5,2,1));
    println!("{}", op!(5,2,2));
    println!("{}", op!(5,2,3));
    println!("{}", op!(5,2,4));
    println!("{}", op!(5,2,5));
    println!("{}", op!(5,2,6));
}
